In the past, apparatuses capable of generating 3-dimensional medical image data (hereinafter referred to as volume data) have been practically used as medical image diagnostic apparatuses such as an X-ray CT (computed tomography) apparatus, an MRI (magnetic resonance imaging) apparatus, or an ultrasonic diagnostic apparatus. The medical image diagnostic apparatus collects imaging data by imaging a subject and generates volume data by performing image processing on the collected imaging data. Moreover, the medical image diagnostic apparatus generates a display image to be displayed on a monitor by performing a volume rendering process on the generated volume data. Here, the medical image diagnostic apparatus displays an operation screen for receiving operations from an operator on a monitor in synchronization with imaging of a subject or generation or displaying of display images. Moreover, the medical image diagnostic apparatus performs imaging of a subject, generation or displaying of display images, and the like in accordance with an operation received on the operation screen.
On the other hand, in recent years, stereoscopic monitors which enable 2-parallax images imaged from two viewpoints to be perceived stereoscopically using a dedicated device such as stereoscopic glasses have been practically used. Moreover, stereoscopic monitors which enable multi-parallax images (for example, 9-parallax images) imaged from multiple viewpoints to be perceived stereoscopically with the naked eyes of a viewer by using a beam controller such as a lenticular lens have been practically used. The 2-parallax images or 9-parallax images displayed on the stereoscopic monitor are sometimes generated by estimating the depth information of images imaged from one viewpoint and performing image processing on the images using the estimated information.